Yılmaz, Levent
Fickian diffusion of organic penetrants in glassy polymers is formulated as a moving‐boundary problem, and the effect of concentration‐dependent diffusivity on the concentration distribution is investigated. The solutions obtained for concentration‐dependent and constant diffusivity cases are compared. The results show that the concentration distribution curves differ both quantitatively and qualitatively. It is concluded that the sharp advancing boundary between the glassy and rubbery regions is due not only to the discontinuous change in the physical properties of these regions but also to the strong concentration dependency of diffusivity.


On the cryptoannulenic behavior of certain corannulenes
Türker, Burhan Lemi (Informa UK Limited, 1996-01-01)
Cryptoannulenic behavior of certain corannulenes is investigated within the Framework of Huckel molecular orbital theory. It has been found that the cryptoannulenic behavior of the corannulenes studied, generally arises from the type of their individual peripheral rings (4m or 4m + 2) but not from the type of the inner or outer periphery of the whole corannulene system.
Reactive extrusion of poly(ethylene terephthalate)-(ethylene/methyl acrylate/glycidyl methacrylate)-organoclay nanocomposites
Alyamac, Elif; Yılmazer, Ülkü (Wiley, 2007-04-01)
This study was conducted to investigate the effects of component concentrations and addition order of the components on the final properties of ternary nanocomposites composed of poly(ethylene terephthalate), organoclay, and an ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) terpolymer acting as an impact modifier for PET. In this context, first, the optimum amount of the impact modifier was determined by melt compounding binary PET-terpolymer blends in a corotating twin-screw extruder. The amount...
A new soluble conducting polymer and its electrochromic devices
YİLDİZ, UMİT HAKAN; SAHİN, ELİF; Akhmedov, IM; Tanyeli, Cihangir; Toppare, Levent Kamil (Wiley, 2006-04-01)
A new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1-(1-phenylethyl)-2,5-di(2-thienyl)-1H-pyrrole (PETPy). Of which the chemical method produces a polymer that is completely soluble in organic solvents. The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (H-1 and C-13 NMR) and Fourier transform infrared (FTIR) spectroscopy. The average molecular weight has been determined by gel permeation chrom...
Türker, Burhan Lemi (Informa UK Limited, 2009-01-01)
A quantum chemical study, based on DFT theory is presented which considers certain selenium-containing naphthalene derivatives, including a keto group together with a Se atom embedded in either a five- or six-membered ring fused with naphthalene moiety. The corresponding enol structures also are considered. The quantum chemical and IR data collected are analyzed and NICS(0) values have been obtained.
On the possibility of Si-60 structure - An AM1 treatment
Türker, Burhan Lemi (Informa UK Limited, 1999-01-01)
A semiempirical treatment at the level of AMI type calculations has been carried out for Si-60 structure and compared with C-60 It has been found that Si-60 is more endothermic and thus less stable. Moreover, silicon substitutional doping on the periphery of hexagonal rings is more destabilizing than the I:ase involving periphery of the pentagonal rings in the structure of C-60.
Citation Formats
I. TOSUN and L. Yılmaz, “ON THE FICKIAN DIFFUSION OF ORGANIC PENETRANTS IN GLASSY-POLYMERS,” POLYMER ENGINEERING AND SCIENCE, pp. 1043–1045, 1982, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39606.